Medical probes have the ability to provide images from inside the patient's body. Considering the potential damage to a human body caused by the insertion of a foreign object, it is preferable for the probe to be as small as possible. Additionally, the ability to image within small pathways such as small vessels, small ducts, small needles, cracks etc., requires a small probe size.
One useful medical probe employs a spectrally encoded endoscopy (“SEE”), which is a miniature endoscopy technology that can conduct high-definition imaging through a mm or sub-mm diameter probe. With SEE, broadband light is diffracted by a grating at the tip of the fiber, producing a dispersed spectrum on the sample. Light returned from the sample is detected using a spectrometer; and each resolvable wavelength corresponds to reflectance from a different point on the sample. The principle of the SEE technique and an SEE probe with a diameter of 0.5 mm, i.e., 500 μm have been described in D. Yelin et al., Nature Vol. 443, 765-765 (2006). SEE can produce high-quality images in two- and three-dimensions.
However, most SEE probes image the wall adjacent to the SEE probe and not the area in front of the probe. These side-view SEE configurations have some limitations, including a limitation of field angle by the grating, aberrations due to the cylindrical side wall of the probe, and that, in use, navigating the inside of organs is challenging without knowledge of what is in front of the probe.
Forward view SEE is preferable for many applications. Forward view SEE is particularly advantageous for applications such as orthopedics, ear, eye and sinuses (EENT), laparoscopy, and pediatric surgery.
One of the technical challenges for fabricating SEE probes has been to conduct forward-view SEE imaging (also called front-view SEE imaging). Previously, SEE probe designs that utilize double-prism grating prism (DP GRISM) have been proposed for forward-view imaging (see U.S. Pat. Pub. 2011/0237892, U.S. Pat. Nos. 8,145,018, and 7,796,270, each of which are herein incorporated by reference as well as Zeidan et al., and Yun et al. (Optics Letters, 39(16):4871-4, 2014; Optics Express, 11(2):120-4, 2003). While this publication demonstrated a spectrally-encoded confocal microscopy (SECM) and SEE probes there are numerous challenges in miniaturizing the probes to a size that is useable in SEE probe. Additionally, these probes are often challenged by either cross-talk between the excitation and detected light (e.g., when using a core/clad configuration for illumination and detection) or the loss of field of view (e.g., when using a separate fiber for detection).
However, there is still need for improved SEE optics and SEE systems, including improved signal level and the effective field of view. Accordingly, it can be beneficial to address and/or overcome at least some of the deficiencies indicated herein above, and thus to provide a new SEE probe that can view forward direction and an apparatus to use such a probe, e.g., for imaging in a small optics.